The overall project objective is to determine the relative importance of aldehyde condensations with neurocellular nucleophiles in the pathophysiology of alcoholism. With highly sensitive and specific mass fragmentography, we propose to characterize tetrahydroisoquinoline alkaloids potentially derived from endogenous neurotransmitter catecholamines during alcohol intoxication and withdrawal in animals, both in the presence and absence of pharmacological drugs. The development of an GC/MS analytical method for the assay of certain biogenic aldehydes, endogenous intermediates possibly elevated by alcohol metabolism, and the application of this method in studies on biogenic aldehyde metabolism and condensations, are also proposed. The alkaloidal condensation products are to be investigated for their effects on endogenous neuroamine biosynthesis and concentrations.